Leading directions in the SMEFT: Renormalization effects

The stability of the electroweak scale, challenged by the absence of deviations in flavor physics, prompts the consideration of SMEFT scenarios governed by approximate SM flavor symmetries. This study examines microscopic theories that match onto a set of $U(3{)}^5$-symmetric dimension-6 operators. Renormalization group (RG) mixing from the ultraviolet to the electroweak scale yields significant phenomenological constraints, particularly pronounced for UV-motivated directions. To demonstrate this, we explore a complete suite of tree-level models featuring new spin-0, spin-$1/2$, and spin-1 fields, categorized by their irreducible representations under the flavor group. We find that for the leading directions, corresponding to a single-mediator dominance, RG mixing effects occasionally serve as the primary indirect probe.

Figure 1

Representative RG diagrams: See Sec. 2 for details.

Figure 2

The leading EFT and direct searches constraints at the 95% CL in the mass-coupling plane of the scalar diquark ${\omega }_1\sim {\overline{\mathbf{6}}}_q$. See Sec. 4b for details.